Assessment of a two-step nitrification model for activated sludge

• Published in: Water research (Oxford) 1996, Vol.30 (4), p.939-953
• Main Authors: Ossenbruggen, Paul J., Spanjers, Henri, Klapwik, Abraham
• Format: Article
• Language: English
• Subjects: activated sludge; Applied sciences; Biological and medical sciences; Biological treatment of waters; Biotechnology; Environment and pollution; Environmental Technology; Exact sciences and technology; experimental design; Fundamental and applied biological sciences. Psychology; General purification processes; Industrial applications and implications. Economical aspects; Mathematical models; Michaelis-Menten; Milieutechnologie; modeling; Monod; Nitrification; nonlinear regression; oxygen uptake rate; oxygen utilization rate; Pollution; Q1; respiration rate; Sectie Milieutechnologie; Sewage sludge; Sodium compounds; Sub-department of Environmental Technology; Wastewaters; Water treatment and pollution; WIMEK
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/0043-1354(95)00236-7

The objective of developing empirical models with well determined parameters is to obtain a better understanding of the nitrification of activated sludge. The D-optimal experimental design criterion and nonlinear regression analysis were used to obtain precise parameter estimates. Our experiment consisted of a series of 14 batch runs where activated sludge was spiked with ammonium chloride and sodium nitrite individually and in combination. Specific respiration rate, the ratio of respiration rate to mixed liquor suspended solids concentration, was used as the model response variable. Empirical models for specific respiration rate were specified as piecewise, Monod type functions of ammonium and nitrite concentration. Statistical methods were used to evaluate the effects of nonlinearity and parameter correlation on the models. The effect of experimental design on model specification and on parameter estimation is discussed.